1. Field:
The subject apparatus is in the field of medical apparatus, specifically apparatus involving injection of liquids into patients. More specifically, it is in the field of such apparatus which can be operated and controlled by a patient. Such apparatus is particularly applicable to the intravenous administrations of medicine intended to reduce and/or eliminate pain, i.e. pain medicine.
2. Prior Art:
It has been well established that the effectiveness of the administration of pain medicine is significantly enhanced when the medicine use can be controlled by the patient, rather than the standard procedure involving a nurse each time medicine is needed. The enhancement is manifested in terms of improvement of the patient's comfort relative to the amounts of medicine required and any adverse side effects related to the amount used and in terms of less nurse time required. With patient control, considerably less medicine is required to achieve specific levels of pain relief and the chances of and degrees of severity of side effects are correspondingly reduced.
Several kinds of patient controlled apparatus are commercially available. Generally the commercially available apparatus incorporates relatively complex electronic and electro-mechanical apparatus which enables the patient to administer an incremental dose of the pain medicine and prevents further administration for a time known as a lockout interval. The purpose of the lockout interval is to allow each dose to have its maximum effect before the next dose can be administered. The amount of medicine in each dose and the length of the lockout interval are set by the medical staff and not accessible to the patient. The commercially available apparatus is considered to be limited in its use by its cost, complication and, in some cases, questionable safety. The one non-electronic, less expensive apparatus known to be commercially available is considered to lack necessary fail-safe features.
In view of the above, a primary objective of the subject invention is provision of a patient-controlled apparatus more generally affordable than known electronic electro-mechanical PCAs. It is a further objective to provide such apparatus which is inherently safer than known apparatus regardless of cost. A still further objective is that the apparatus be easily and readily operable by both patients and medical personnel. Still further objectives may be apparent to those skilled in the art from the following descriptions of the invention.